<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Scroll Animation</title>
    <script>
        window.onload = function(){
            const boxes = document.querySelectorAll('.box')
            window.addEventListener('scroll',checkBoxes)
            checkBoxes()
            function checkBoxes(){
                const triggerBottom = window.innerHeight / 5 * 4
                console.log(boxes);
                boxes.forEach(box=>{
                    const boxTop = box.getBoundingClientRect().top
                    if(boxTop < triggerBottom){
                        box.classList.add('show')
                    }else{
                        box.classList.remove('show')
                    }
                })
            }
        }
    </script>
    <style>
        *{
            box-sizing: border-box;
        }
        body{
            background-color: #efedd6;
            font-family: 'Roboto',sans-serif;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            margin: 0;
            overflow-x: hidden;
        }
        h1{
            margin: 10px;
        }
        .box{
            background-color: steelblue;
            color: #fff;
            display: flex;
            align-items: center;
            justify-content: center;
            width: 400px;
            height: 200px;
            margin-top: 20px;
            border-radius: 10px;
            box-shadow: 2px 4px 5px rgba(0, 0, 0, 0.3);
            transform: translateX(400%);
            transition:  transform 0.4s ease;
        }
        .box:nth-of-type(even){
            transform: translate(-400%);
        }
        .box.show{
            transform: translateX(0);
        }
        .box h2{
            font-size: 45px;
        }
    </style>
</head>
<body>
    <h1>Scroll to see the animation</h1>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
    <div class="box">
        <h2>Content</h2>
    </div>
</body>
</html>